Material handling system

ABSTRACT

An improved material handling system includes a main track for guiding movement of a vehicle to and from aisles between adjacent rows of bins. The vehicle is transferred from the main track to tracks in a selected aisle by operating transfer arms on the vehicle to pivot transfer rails forming lengths of the main track into alignment with the aisle tracks. Once the vehicle has entered the selected aisle and moved beyond the transfer rails, biasing springs pivot the transfer rails back into alignment with the main track where the transfer rails are held in place by latch assemblies. When the vehicle starts to leave the selected aisle and is approaching the main track, the vehicle operates trip linkages to release the latch assemblies. Continued movement of the vehicle toward the main aisle operates other linkages to pivot the transfer rails back into alignment with the aisle tracks against the influence of the biasing springs.

United States Patent 1 91 Pipes [451 May 1, 1973 41 MATERIAL HANDLINGSYSTEM [75] Inventor: George R. Pipes, South Euclid, Ohio [73 Assignee:Eaton Corporation, Cleveland, Ohio [22] Filed: Feb. 22, 1971 [21 Appl.No.: 117,321

[52] US. Cl ..104/48, 104/130 [51 Int. Cl. ..B60s 13/02 [58] Field ofSearch ..104/40, 48, 49, 50, 104/99, 100, 96, 101, 130; 214/164 A, 16.4

[56] References Cited UNITED STATES PATENTS 3,485 ,390 12/ l 969 Atwater..104/48 3,432,046 3/ l 969 Krusinski. 104/48 3,170,41 l 2/1965 Howard104/40 Primary Examinep-Drayton E. Hoffman Attorney-Yount and Tarolli 57 ABSTRACT An improved material handling system includes a main trackfor guiding movement of a vehicle to and from aisles between adjacentrows of bins. The vehicle is transferred from the main track to tracksin a selected aisle by operating transfer arms on the vehicle to pivottransfer rails forming lengths of the main track into alignment with theaisle tracks. Once the vehicle has entered the selected aisle and movedbeyond the transfer rails, biasing springs pivot the transfer rails backinto alignment with the main track where the transfer rails are held inplace by latch assemblies. When the vehicle starts to leave the selectedaisle and is approaching the main track, the vehicle operates triplinkages to release the latch assemblies. Continued movement of thevehicle toward the main aisle operates other linkages to pivot thetransfer rails back into alignment with the aisle tracks against theinfluence of the biasing springs.

9 Claims, 8 Drawing Figures Patented May 1, 1973 4 Sheets-Sheet wrewroeGEORGE A. P/PEJ MATERIAL HANDLING SYSTEM This invention relatesgenerally to a new and improved material handling apparatus and, moreparticularly, to a material handling system wherein a vehicle isutilized to transport materials to and from storage locations.

In automatic warehousing systems, stacker cranes and other vehicles areutilized to transport materials to and from rows of bins. In such asystem, a vehicle moves along a transfer aisle until it reaches a binaisle along which a selected bin is disposed. The vehicle then movesalong this bin aisle to the selected bin. Various types of transferarrangements have heretofore been provided to guide this movement of thevehicle from the transfer aisle to the bin aisle. However, for onereason or another, these known transfer arrangements have been somewhatunsatisfactory in their operation.

In accordance with the present invention, a pair of transfer rails aremovable between a first or an initial position in which they are alignedwith a transfer track which extends along a transfer aisle and a second'or transfer position in which the transfer rails form an extension ofan aisle track which guides movement of the vehicle along a bin aisle.The transfer rails, when in the initial position, guide movement of thevehicle along the transfer aisle. When the vehicle is to enter a binaisle associated with these transfer rails, the transfer rails arepivoted in opposite directions so that they are aligned with and form anextension of tracks disposed on opposite sides of the bin aisle. Thisenables the transfer rails to guide movement of the vehicle into the binaisle. When the vehicle is to leave the bin aisle, the transfer railsguide the'movement of the vehicle back into the transfer aisle. Thetransfer rails are then pivoted back into alignment with the transfertrack to guide movement of the vehicle along the transfer aisle. Thetransfer rails are pivoted between the position in which they arealigned with the transfer track and the position in which they arealigned with the bin aisle tracks by arms which are mounted on thevehicle. A

transfer assembly invented by Richard J. Park and claimed in copendingapplication Ser. No. l 17,422, filed on Feb. 22, 1971, and entitledMaterial Handling System Transfer Assembly" is advantageously used inassociation with the transfer rails so that they are pivoted back intoalignment with the transfer track after a vehicle has entered a binaisle and are automatically pivoted into alignment with the aisle tracksin the bin aisle when a vehicle is to leave the bin aisle.

Accordingly, it is an object of this invention to provide a new andimproved material handling system which includes movable transfer railsfor guiding movement of a vehicle between a transfer aisle and a binaisle.

Another object of this invention is to provide a material handlingsystem which includes a new and improved transfer arrangement forguiding movement of a vehicle from a track in a transfer aisle to atrack in a bin aisle and wherein lengths of the transfer track arepivoted by the vehicle to transfer the vehicle from the one track to theother.

Another object of this invention is to provide a new and improvedmaterial handling system wherein a pair of lengths of track are pivotedby a vehicle to transfer the vehicle from one track assembly to anothertrack assembly, the vehicle being equipped with a pair of arms to effectthe pivoting movement of the lengths of track.

Another object of this invention is to provide a new and improvedmaterial handling system which includes first and second tracksextending transversely to each other for guiding movement of a vehiclealong transversely extending paths and wherein a transfer rail ismovable between a first position in which it is aligned with the firsttrack and a second'position in which it is aligned with the secondtrack, the transfer rail being movable from the first position to thesecond position by an operator arrangement on the vehicle to enable thetransfer rail to guide movement of the vehicle along one of the tracksand then along the other.

Another object of this invention is to provide a new and improvedmaterial handling system in accordance with the next preceding objectand wherein the operator arrangement on the vehicle includes an armwhich is engageable with the transfer rail and a drive arrangement formoving the arm between a position extending parallel to the first trackand a position extending parallel to the second track to thereby movethe transfer rail between its first and second positions.

Another object of this invention is to provide a new and improvedmaterial handling vehicle for use in transporting materials along afirst track and along, a second track extending transversely to thefirst track wherein the vehicle includes an arm arrangement for guidingmovement of the vehicle along the tracks and for moving a length oftrack from a position in which a longitudinal axis of the length oftrack extends parallel to the first track to a position in which thelongitudinal axis of the length of track extends parallel to the secondtrack to thereby enable the vehicle to move along the length of trackfrom a position in which the arm engages the first track to a positionin which the arm engages the second track.

These and other objects and features of the present invention willbecome more apparent upon a consideration of the following descriptiontaken in connection with the accompanying drawings wherein:

FIG. 1 is a schematic illustration of a material handling systemconstructed in accordance with the present invention and including avehicle which is movable from a main aisle extending transversely to arow of bins to an aisle extending along the row of bins;

FIG. 2 is a schematic illustration of a material handling vehicleconstructed in accordance with the present invention;

FIG. 3 is an enlarged plan view, taken generally along line 3-3 of FIG.2, illustrating an operator arrangement on the vehicle for use ineffecting a transfer of the vehicle from a main track extending alongthe main aisle to aisle tracks extending along a row of bins;

FIG. 4 is an enlarged plan view of a portion of the operator assembly ofFIG. 3 and illustrating the relationship of the operator assembly to atransfer arm when the transfer arm is positioned to engage an aisletrack;

FIG. 5 is an elevational view, taken generally along line 5-5 of FIG. 4,illustrating the relationship of the operator assembly and transfer armto an aisle track;

FIG. 6 is a plan view illustrating the relationship of a transfer railto a latch assembly for retaining the transfer rail in alignment with.the main track, a trip assembly for releasing the latch assembly, and atransfer rail swing assembly for effecting movement of the transfer railinto alignment with an aisle track;

FIG. 7 is an elevational view, taken generally along line 7-7 of FIG. 6,further illustrating the relationship between the transfer rail, latchassembly, and transfer rail swing assembly; and

FIG. 8 is a plan view, generally similar to FIG. 6, illustrating thetransfer rail in alignment with the aisle track.

A material handling system 10 constructed in accordance with the presentinvention includes a plurality of rows 12, 14, 16, 18 and 20 of bins 22for storing materials. Material handling vehicles 26 and 28 move along atransfer or main aisle 30 which extends perpendicular to the rows 12-20of bins. When a material handling vehicle is adjacent to a selected binor secondary aisle, such as the aisle 32 between the rows 14 and 16 ofbins or the aisle 34 between the rows 18 and 20 of bins, the materialhandling vehicle moves from the transfer or main aisle 30 down the binor secondary aisle until it is adjacent to a selected bin. In theillustrated embodiment of the invention, the material handling vehicles26 and 28 are stacker cranes (see FIG. 2) each of which includes ashuttle assembly 38 which is extendable to position a container 40 in aselected bin. Of course, the stacker cranes 26 and 28 can be utilized toretrieve containers, such as the container 40, from a selected bin.Although the transfer aisle 30 is referred to herein as the main aisle,it should be understood that the stacker cranes 26 and 28 perform workoperations in the bin aisles 32 and 34 which are referred to herein assecondary aisles.

The stacker crane 26 is of a known construction and rides on a cushion"of air blown against a floor or other surface 44, as is known (see FIGS.2 and 3). Of course, other known drive arrangements could be utilized ifdesired and the present invention is not limited to any particular drivearrangement. The stacker crane 26 includes a rectangular frame or base50 with an upwardly extending mast 52 which engages a track arrangement54 on the ceiling 56 ofa building to prevent the mast from tipping. Theceiling track 54 is interrupted at the bin or secondary aisles 32 and 34to enable the stacker crane 26 to move from the transfer or main aisle30 to the bin aisles.

The shuttle assembly 38 is movable vertically up and down along the mast52 to position the container 40 vertically relative to a bin 22 which isto receive the container. Suitable power tracks can be provided adjacenteither the base frame 50 or the ceiling track arrangement 54 to transmitelectrical power to motors within a body 58 of the stacker crane 26. Thestacker crane 28 is of the same generally known construction as thestacker crane 26 and will not be further described herein to avoidprolixity of description.

Although the stacker cranes 26 and 28 have a trackless drive directly tothe floor 44, a transfer or main track 62 is engaged by the stackercranes to guide their movement in the direction of the arrows 64 alongthe transfer or main aisle 30. Similarly, secondary or aisle tracks 66,68, 70 and 72 are disposed along the rows of bins 14-20 to guidemovement of the stacker cranes 26 and 28 along the aisles 32 and 34 in adirection perpendicular to the transfer or main aisle 30.

It should be noted that the aisle tracks 66-72 terminate just short ofand do not intersect the main track 62.

In accordance with the present invention, transfer assemblies 76 and 78are operated by the stacker cranes 26 and 28 to guide their movementfrom the main track 62 to the secondary or aisle tracks 66-72 when thestacker cranes enter the secondary aisles 32 and 34. The transferassemblies 76 and 78 include transfer rails 80, 82, 84 and 86 formed ofstraight lengths of the main track 62. The transfer rails 80-86 normallyor initially span the secondary aisles 32 and 34 so as to guide movementof the stacker cranes 26 and 28 along the main aisle 30 past theentrances to the secondary aisles. When a stacker crane is to enter asecondary aisle 32 or 34, the stacker crane moves into alignment withthe entrance to the selected secondary aisle. The transfer rails arethen moved into alignment with the tracks in the selected secondaryaisle to guide movement of the stacker crane from the main aisle intothis secondary aisle.

The track lengths or transfer rails 84 and 86 are shown in FIG. 1spanning the secondary aisle 34 to guide movement of the stacker crane28 along the main aisle 30 past the entrance to the secondary aisle 34.On the other hand, the track lengths or transfer rails 80 and 82 areshown pivoted from their aisle spanning positions to a transfer positionin which they extend parallel to the longitudinal axis of the secondaryor aisle tracks 66 and 68 to guide movement of the stacker crane 26 fromthe main aisle 30 to the secondary aisle 32. Of course, once the stackercrane enters the secondary aisle 32, the aisle or secondary tracks 66and 68 guide movement of the stacker crane along the aisle 32, that isin the direction of the arrows 90. After the stacker crane 26 hasentered the secondary aisle 32, the transfer rails 80 and 82 areadvantageously pivoted back to their aisle spanning positions in whichthey can guide movement of the stacker crane 28 along the main aisle 30past the entrance to the secondary aisle 32.

The stacker crane 26 includes a pair of transfer arms 102 and 104 whichengage the main track 62 and are pivotal to move the transfer rails 80and 82 or 84 and 86 into alignment with their associated aisle tracks.The transfer arms 102 and 104 are pivotally mounted at 106 and 108 (FIG.3) on the frame 50 of the stacker crane 26. A drive assembly 112 isconnected with the transfer arms 102 and 104 to effect pivoting movementof the transfer arms and transfer rails engaged by the arms.

The drive assembly 112 includes a drive linkage 114 which is driven by amotor 116 (see FIGS. 4 and 5) through a gear reduction unit 118 to pivotthe transfer arm 102 in a clockwise direction (as viewed in FIG. 3)about its mounting 106. Simultaneously with this movement of thetransfer arm 102, the drive assembly 112 pivots the transfer arm 104 ina counter clockwise direction (as viewed in FIG. 3) about its mounting108. Since the transfer rails 80 and 82 are engaged by the arms 102 and104, this pivotal movement of the arms moves the transfer rails 80 and82 from their aisle spanning positions extending across the secondaryaisle 32 to their transfer positions extending parallel to the aisletracks 66 and 68 (see FIG. 1). Thus, the transfer arms 102 and 104 arepivotal from positions extending outwardly of the stacker crane 26 topositions beside the frame 50 of the stacker crane to move the transferrails 80 and 82 into alignment with the aisle tracks 66 and 68. However,it should be understood that the transfer arms 102 and 104 could bemounted for movement from a position extending along the front of theframe 50 to an outwardly extending position to pivot the transfer rails80 and 82 into alignment with the aisle tracks 66 and 68. In addition,it should be understood that although a pair of transfer arms 102, 104have been illustrated herein to pivot a pair of relatively shorttransfer rails 80 and 82, a single transfer arm could be mounted on thestacker crane 26 to pivot a single relatively long transfer rail.

The transfer arms 102 and 104 are held in a position extending parallelto the longitudinal axis of the main track 62, that is in the positionof transfer arms 122 and 124 of the stacker crane 28 in FIG. 1, by apair of struts 128 and 130 (FIG. 3). The struts 128 and 130 arepivotally connected at 134 and 136 to outer end portions of the transferarms 102 and 104. The inner end of the strut 128 is pivotally connectedat 138 to a slide block 140 which is movable along a channel 142 definedbetween a pair of guides 144 and 146 mounted on the frame 50. The innerend portion of the strut 130 is connected to the frame 50in the samemanner as in which the strut 128 is connected with the frame.

When the stacker crane 26 is moving along the main track 62 with thetransfer arms 102 and 104 extending parallel to the longitudinal axis ofthe main track, the transfer arms interconnect the stacker crane and themain track. Since the main track 62 guides movement of the stacker crane26 along the main aisle 30, it is important that the transfer arms 102and 104 be held against pivotal movement relative to the frame 50 of thestacker crane. Accordingly, a latch assembly 154 engages the slide block140 to retain the strut 128 against movement along the channel 142. Whenthe transfer arm 102 is to be pivoted inwardly toward the frame 50 ofthe vehicle by operation of the drive assembly 112, a release solenoid156 on the frame 50 is energized to operate the latch assembly 154 andrelease the slide block 140 for movement along the channel 142 in thedirection of the arrow 160. This enables the transfer arm 102 to bepivoted in a clockwise direction toward the frame 50 of the stackercrane 26 by the drive assembly 112, Of course, a latch assembly andsolenoid similar to the latch assembly and solenoid 154 and 156, areassociated with the strut 130 to hold the transfer arm 104 againstpivotal movement when the stacker crane 26 is moving along the maintrack 62.

The drive assembly 112 is operable to simultaneously pivot the transferarms 102 and 104 and the transfer rails 80 and 82 through ninety degreesrelative to the frame 50 of the stacker crane 26. Accordingly, thelinkage 114 of the drive assembly 112 includes a swivel plate 170 whichis rotatable relative to the frame 50 by a drive or output shaft 172(FIGS. 3, 4 and 5) of the gear reducer 118. Rotational movement of theswivel plate 170 moves pivot arms 176 and 178 to rotate crank arms 180and 182 through 90". Of course, this rotational movement of the crankarms 180 and 182 pivots support pins 184 and 186 which are connected tothe transfer arms 102 and 104. The inner-connection between the supportpin 184 and the transfer arm 104 includes a connector plate 190 (FIG. 5)which is fixably connected to the transfer arm 104 and the support pin184. Although only the mounting for the transfer arm 104 on the supportpin 184 is illustrated herein, it should be understood that the transferarm 102 is mounted on the support pin 186 in the same manner.

From the foregoing, it can be seen that the stacker crane 26 includes apair of transfer arms 102 and 104 which extend parallel to and engagethe main track 62 with rollers, similar to rollers 196 and 198 of FIG.5, to guide movement of the stacker crane along the main aisle 30. Whenthe stacker crane 26 reaches the entrance to a selected secondary aisle,such as the aisle 32, the transfer arms 102 and 104 are pivoted through90 toward the frame of the stacker crane by the drive assembly 112. Thismovement of the transfer arms 102 and 104 pivots the transfer rails 80and 82 into alignment with the aisle tracks 66 and 68. When the transferrails 80 and 82 have been pivoted into alignment with the aisle tracks66 and 68, the stacker crane is moved forward along the aisle 32. As thestacker crane 26 moves along the aisle 32, the rollers on the transferarms 102 and 104 move out of engagement with the transfer rails 80 and82 and into engagement with the aisle tracks 66 and 68. Although thetransfer arms 102 and 104 have been described herein in connection withthe stacker crane 26, it is contentplated that they could be used inassociation with other types of material handling vehicles.

A separate transfer rail swing or operator assembly is advantageouslyassociated with each of the pivotal transfer rails 80-86 to move theassociated transfer rail between the initial position and the transferposition. Thus, a transfer rail swing or operator assembly 210 (seeFIGS. 6, 7 and 8) is associated with the transfer rail 82 to effectmovement of the transfer rail between the initial position in which itis aligned with the main track 62 (FIGS. 6 and 7) and a second ortransfer position in which the transfer rail 82 is aligned with theaisle track 68 (FIG. 8). As was previously explained,the transfer arms102 and 104 on the stacker crane 26 pivot the transfer rail 82 from itsinitial position in which it forms part of the main track 62 to thetransfer position in which it is aligned with the aisle track 68.However, the swing or operator assembly 210 pivots the transfer rail 82back into alignment with the main track 62 once the stacker crane 26 hasentered the secondary aisle 32. This enables the transfer rail 82 toguide movement of another stacker crane, for example, the stacker crane28, along the main aisle 30 while the stacker crane 26 is in thesecondary aisle 32. When the stacker crane 26 approaches the main aisle30 to leave the secondary aisle 32, the transfer rail swing or operatorassembly 210 pivots the transfer rail 82 back into alignment with theaisle track 68 to enable the transfer rail 82 to guide movement of thestacker crane 26 as it returns to the main aisle 30.

The transfer rail 82 is held or retained'in alignment with thelongitudinal axis of the main track 62 by a latch assembly 214 which ismounted on a support frame 216 extending along the main aisle 30. Thelatch assembly 214 includes a retaining latch or pawl 220 which ispivotally mounted on the support frame 216 for movement between anengaged or latched position and a release position. When it is in thelatched position, the latch pawl 220 engages the rail 82 to hold therail against pivotal movement relative to the main track 62. When thelatch pawl 220 is released, a retaining nose or end portion 222 of thelatch pawl is raised upwardly (from the position shown in FIG. 7) toclear the transfer rail 82 so that it is free to move into alignmentwith the aisle track 68 (see FIG. 8).

As the stacker crane 26 moves along the main track 62 into alignmentwith the entrance to the secondary aisle 32, the latch pawl 220 ispivoted upwardly by camming engagement of the transfer arm 104 with thenose 222 of the latch pawl. This releases the latch assembly 214. Thetransfer arm 104 is then moved inwardly toward the frame 50 of thestacker crane 26 by operation of the drive assembly 112 in the mannerpreviously explained. Since the rollers 196 and 198 engage the transferrail 82 (FIG. this movement of the transfer arm 104 pivots the transferrail 82 in a counter clockwise direction (as viewed in FIG. 6) about apivot mounting 230. This results in the transfer rail 82 moving out ofalignment with the main track 62, through the position shown in FIG. 3,and to the transfer position (FIG. 8) in which the transfer rail isaligned with the aisle track 68. Of course, the transfer rail 80 ispivoted simultaneously with the transfer rail 82 by the transfer arm 102of the stacker crane 26 (FIG. 3).

Once the transfer rails 80 and 82 have been moved into alignment withthe aisle tracks 66 and 68, the stacker crane 26 can enter the aisle 32.It should be noted that the stacker crane 26 moves along the main aisle30 in a direction parallel to its transverse axis 231 (see FIG. 1) andthen moves along the secondary aisle 32 in a direction parallel to itslongitudinal axis 232. However, the transfer arms 102 and 104 engageguide tracks to guide movement of the stacker crane 26 along either themain aisle 30 or the secondary aisle 32. Thus, the transfer arms 102 and104 extend parallel to the axis 231 and the main track 62 when thestacker crane 26 is moving along the main aisle 30. Similarly, when thestacker crane 26 is moving along the secondary aisle 32, the transferarms 102 and 104 extend parallel to the longitudinal axis 232 of thestacker crane and engage the aisle tracks 66 and 68 -to guide movementof the stacker crane along these tracks.

Once the stacker crane has entered the secondary aisle 32 and has moveda short distance beyond the transfer rail 82, a biasing spring 240pivots the transfer rail from the transfer position of FIG. 8 to theinitial position of FIG. 6. The biasing spring 240 extends between astationary support bracket 242 and a crank arm 244 which is connected tothe pivot mounting 230 for the transfer rail 82. When the transfer rail82 is pivoted from the initial position to the transfer positionimmediately prior to entrance of the stacker crane 26 into the secondaryaisle 32, the crank arm 244 is pivoted in a counter clockwise directionfrom the position shown in FIG. 6 to the position shown in FIG. 8 with aresulting stretching of the biasing spring 240. Therefore, when thetrailing end of the stacker crane 26 has moved a short distance beyondthe transfer rail 82, the biasing spring 240 pivots the crank arm 244and transfer rail 82 in a clockwise direction about the pivot mounting230 to move the transfer rail into alignment with the main track 62. Ofcourse, the latch assembly 214 will then engage the transfer rail 82 toretain it in alignment with the main track 62.

When the stacker crane 26 leaves the aisle 32, the transfer rail 82 mustbe swung or pivoted out of alignment with the main track 62 and intoalignment with the aisle track 68 to guide movement of the stacker craneout of the aisle 32. Accordingly, when the stacker crane 26 approachesthe main aisle 30, a trip assembly 250 is actuated to operate the latchassembly 214 and release the transfer rail 82 for movement about thepivot mounting 230. Continued movement of the stacker crane toward themain aisle 30 actuates a swing operator assembly 252 to effect pivotalmovement of the transfer rail 82 from the initial position (FIG. 6) tothe transfer position shown (FIG. 8). Thus, the transfer rail 82 ismoved from a position in which it is aligned with the main track 62(FIG. 6) to a position in which it is aligned with the aisle track 68(FIG. 8) against the influence of the biasing spring 240 in response tomovement of the stacker crane 26 along the aisle 32 toward the mainaisle 30.

The trip assembly 250 for releasing the latch assembly 214 includes atrip arm 258 which is pivotally mounted on a support bracket 260 and ismovable to the actuated position of FIG. 8 to release the latch assembly214. The trip arm 258 is connected with the latch assembly 214 by aflexible cable 262. The flexible cable 262 is in turn connected to alatch trip plate or bar 266 (FIG. 7) which is pivotally mounted at 268on a support bracket 270. The trip plate or bar 266 is connected withthe latch pawl 220 by a link 274.

When the stacker crane 26 moves along the aisle 32 toward the main aisle30, the stacker crane engages the trip arm 258 which extends into theaisle 32 (see FIG. 6). Continued movement of the stacker crane 26 towardthe main aisle 32 pivots the trip arm 258 to its actuated position (FIG.8). Moving the trip arm 258 to its actuated position causes the cable262 to rotate the trip plate 266 in a clockwise direction (as viewed inFIG. 7) about its pivot mounting 268. This rotational movement of thetrip plate 266 is transmitted by the link 274 to the latch pawl 220 tothereby rotate the latch pawl in a counter clockwise direction (asviewed in FIG. 7) about its pivot mounting 280 against the influence ofa biasing spring 282. This pivotal movement of the latch pawl 220releases the transfer rail 82 for pivoting movement-from its initialposition (FIG. 6) to the transfer position (FIG. 8).

Still further movement of the stacker crane toward the main aisle 30results in the swing or operator assembly 252 being actuated by thestacker crane to pivot the transfer rail 82 from the initial position tothe transfer position against the influence of the biasing spring 240.Thus, the operator assembly 252 includes a swing bar 286 which ispivotally mounted at 288 on a generally V-shaped support bracket 292.The support bracket 282 includes a pair of legs 294 and 296 (see FIGS.6, 7 and 8) which are connected to a mounting plate 300 secured to theaisle track 68. A trip or actuator arm 304 is pivotally mounted at 306on the swing arm 286 and is biased against a detent or stop 308 by aspiral spring 312. This mounting enables the actuator arm 304 to movethe swing arm 286 in only a clockwise direction about the pivot mounting288.

When a leading end portion of the stacker crane 26 engages the actuatorarm 304 as it moves toward the main aisle 30, the actuator arm causesthe swing or operator bar 286 to pivot in a clockwise direction (asviewed in FIG. 6) to the actuated position shown in FIG. 8. This pivotalmovement of the swing or operator bar 286 is transmitted to the crankarm 244 by a connector rod 316 to rotate the crank arm 244 and transferrail 82 through90" from the initial position (FIG. 6) to the transferposition (FIG. 8) against the influence of the biasing spring 240.

Once the transfer rail 82 has been moved to the transfer position,continued movement of the stacker crane 26 toward the main aisle 30moves rollers 318 (FIG. 2) out of engagement with the aisle track 68 andinto engagement with the transfer rail 82. Continued movement of thestacker crane 26 toward the main aisle 30 moves the rollers 196 and 198on the transfer arm 104 into engagement with the transfer rail 82 (FIG.5)v Once the stacker crane 26 has moved into the main aisle 30 (FIG. 1),the transfer arms I02 and 104 on the stacker crane 26 are pivoted tomove the transfer rails 80 and 82 from the transfer positions (FIG. 1)to their initial positions spanning the aisle 32. As the transfer rails80 and 82 are swung into their initial positions by the transfer arms104, the transfer rails will be engaged by latch assemblies, similar tothe latch assembly 214 (FIG. 7). This retains the transfer rails 80 and82 against pivotal movement as the stacker crane 26 moves along the maintrack 62. Once this has occurred, the stacker crane 26 is free to movealong the main aisle 30 in the direction of the arrows 64.

Although only the transfer rail swing or operator assembly 210associated with the transfer rail 82 has been fully described herein, itshould be understood that a similar operator assembly is associated withthe transfer rail 80. Therefore, the transfer rails 80 and 82 are movedtogether in unison by their associated operator assemblies to swing thetransfer rails back to their initial positions spanning the aisle 32once the stacker crane 26 has entered the aisle 32. In addition, thetransfer rail 80 is swung to its transfer position (see FIG. 1) byoperation of a swing or operator assembly of the same construction asthe swing operator assembly 252, at the same time that the transfer rail82 is swung tov its transfer position. In addition, it should beunderstood that transfer rail swing or operator assemblies, of the sameconstruction as the transfer rail swing assembly 210 of FIG. 8, areassociated with the transfer rails 84 and 86 to move them in the samemanner as previously explained in connection with the transfer rails 80and 827 In view of the foregoing remarks, it can be seen that thematerial handling system 10 includes a main track 62 for guidingmovement of the stacker cranes 26 and 28 in the direction of the arrows64. Transfer rails 80, 82, 84 and 86 are mounted in pairs in associationwith the secondary aisles 32 and 34. The transfer rails are pivotalbetween an initial position in which they are aligned with the maintrack 62 and a transfer position in which they are aligned with theassociated aisle tracks 66, 68, 70 and 72. When a stacker crane, such asthe stacker crane 26, is to move from the main aisle to a secondaryaisle, the stacker crane is aligned with the entrance to the aisle andthe transfer arms 102 and 104 on the stacker crane are pivoted to swingthe transfer rails into alignment with the aisle tracks. The stackercrane 26 then moves down the secondary aisle.

When the stacker crane 26 has cleared the swing or pivot arm 286 of thetransfer rail swing assembly 210, the biasing spring 240 will swing theassociated transfer rail back into alignment with the main track 62.

When the stacker crane 26 is to leave the secondary aisle, the stackercrane operates the latch assembly 250 to release the latch 214. Thestacker crane 26 then actuates the swing or operator assembly 252 topivot the associated transfer rail about the pivot mounting 230 intoalignment with the aisle track 62, Once the stacker crane 26 has movedinto the main aisle 30, the transfer arms 102 and 104 on the stackercrane are operated to swing the transfer rails and 82 back to theiraisle spanning positions so that the stacker crane is free to move alongthe main aisle. Although only the transfer arms 102 and 104 for thestacker crane 26 have been fully describedherein, it should beunderstood that the transfer arms 122 and 124 on the stacker crane 28are of the same construction and operate in the same manner as dotransfer arms 102 and 104.

Having described specific preferred embodiments of the invention, thefollowing is claimed:

1. A material handling apparatus comprising a vehicle for use in movingmaterials; first and second track means extending transversely to eachother for guiding movement of said vehicle along transversely extendingpaths; a length of track movable between a first position in which it isaligned with said first track means and a second position in which saidlength of track is aligned with said second track means; and means onsaid vehicle for effecting movement of said length of track from saidfirst position to said second position to enable said length of track toguide movement of said vehicle along one of the paths and then along theother of the paths including an arm movably mounted on said vehicle andengageable with said length of track, and drive means on said vehiclefor moving said arm between a position extending parallel to said firsttrack means and a position extending parallel to said second track meansto move said length of track between its first and second position.

2. A material handling apparatus as set forth in claim 1 wherein saidfirst and second track means extend perpendicular to each other and havelongitudinal axes disposed in a common horizontal plane, said systemfurther including mounting means for supporting said length of track forpivotal movement from said first position through ninety degrees about avertical axis to said second position.

3. A material handling apparatus as set forth in claim 1 wherein saidsecond track means terminates short of a point of intersection with saidfirst track means, said length of track extending from the terminationof said second track means through the point where said first trackmeans would intersect said second track means when said length of trackis in said second position.

4. A material handling apparatus comprising a vehicle for use intransporting materials along a first track and along a second trackextending transversely to the first track, said vehicle comprising aframe and arm means mounted on said frame for engaging the tracks toguide movement of said vehicle along the tracks and for moving a lengthof track from a first position in which a longitudinal axis of thelength of track extends parallel to a longitudinal axis of said firsttrack to a second position in which a longitudinal axis of the length oftrack extends parallel to a longitudinal axis of said second track tothereby enable the vehicle to move along the length of track from aposition in which said arm means engages the first track to a positionin which said arm means engages the second track.

5. A material handling apparatus as set forth in claim 4 furtherincluding drive means for effecting movement of said arm means from oneposition in which said arm means extends parallel to the longitudinalaxis of the first track to another position in which said arm meansextends parallel to the longitudinal axis of said second track tothereby effect movement of the length of track between the first andsecond positions.

6. A material handling apparatus as set forth in claim 4 wherein saidarm means includes a first arm pivotally mounted on one side of saidvehicle and a second arm pivotally mounted on another side of saidvehicle, said vehicle further including drive means for moving saidfirst and second arms from a position in which longitudinal axes of saidarms are coincident with each other and extend parallel to alongitudinal axis of said first track to a second position in which thelongitudinal axes of said arms are spaced apart and extend parallel tothe longitudinal axis of said second track.

7. A material handling apparatus comprising a material handling vehicle,first track means for guiding movement of said vehicle along a mainaisle, a plurality of second track means each of which extends along anassociated one of a plurality of secondary aisles, said second trackmeans terminating short of intersection with said first track means,said first track means including a plurality of pairs of lengths oftrack, each pair of which is movable between a first position spanningan associated one of said secondary aisles to guide movement of saidvehicle along the main aisle past the associated secondary aisle and asecorid position forming an extension between the associated one of saidsecond track means and said first track means to guide movement of saidvehicle from the main aisle into the associated secondary aisle, andmeans on said vehicle for effecting movement of said pairs of lengths oftrack from their first position to their second position.

8. A material handling apparatus as set forth in claim 7 wherein saidmeans on said vehicle for effecting movement of said pairs of lengths oftrack includes means for pivoting one length of track of a pair oflengths of track in a clockwise direction about a first axis and meansfor pivoting the other length of track of the pair of lengths of trackin a counterclockwise direction about a second axis.

9. A material handling apparatus as set forth in claim 8 wherein saidmeans for pivoting said lengths of track includes a first arm pivotallymounted on the vehicle and engageable with the one length of track and asecond arm pivotally mounted on the vehicle and engageable with theother length of track and drive means on the vehicle for simultaneouslypivoting said first and second arms in opposite directions relative tothe vehicle to move a pair oflengths of track from the first position tothe second position.

1. A material handling apparatus comprising a vehicle for use in movingmaterials; first and second track means extending transversely to eachother for guiding movement of said vehicle along transversely extendingpaths; a length of track movable between a first position in which it isaligned with said first track means and a second position in which saidlength of track is aligned with said second track means; and means onsaid vehicle for effecting movement of said length of track from saidfirst position to said second position to enable said length of track toguide movement of said vehicle along one of the paths and then along theother of the paths including an arm movably mounted on said vehicle andengageable with said length of track, and drive means on said vehiclefor moving said arm between a position extending parallel to said firsttrack means and a position extending parallel to said second track meansto move said length of track between its first and second position.
 2. Amaterial handling apparatus as set forth in claim 1 wherein said firstand second track means extend perpendicular to each other and havelongitudinal axes disposed in a common horizontal plane, said systemfurther including mounting means for supporting said length of track forpivotal movement from said first position through ninety degrees about avertical axis to said second position.
 3. A material handling apparatusas set forth in claim 1 wherein said second track means terminates shortof a point of intersection with said first track means, said length oftrack extending from the termination of said second track means throughthe point where said first track means would intersect said second trackmeans when said length of track is in said second position.
 4. Amaterial handling apparatus comprising a vehicle for use in transportingmaterials along a first track and along a second track extendingtransversely to the first track, said vehicle comprising a frame and armmeans mounted on said frame for engaging the tracks to guide movement ofsaid vehicle along the tracks and for moving a length of track from afirst position in which a longitudinal axis of the length of trackextends parallel to a longitudinal axis of said first track to a secondposition in which a longitudinal axis of the length of track extendsparallel to a longitudInal axis of said second track to thereby enablethe vehicle to move along the length of track from a position in whichsaid arm means engages the first track to a position in which said armmeans engages the second track.
 5. A material handling apparatus as setforth in claim 4 further including drive means for effecting movement ofsaid arm means from one position in which said arm means extendsparallel to the longitudinal axis of the first track to another positionin which said arm means extends parallel to the longitudinal axis ofsaid second track to thereby effect movement of the length of trackbetween the first and second positions.
 6. A material handling apparatusas set forth in claim 4 wherein said arm means includes a first armpivotally mounted on one side of said vehicle and a second arm pivotallymounted on another side of said vehicle, said vehicle further includingdrive means for moving said first and second arms from a position inwhich longitudinal axes of said arms are coincident with each other andextend parallel to a longitudinal axis of said first track to a secondposition in which the longitudinal axes of said arms are spaced apartand extend parallel to the longitudinal axis of said second track.
 7. Amaterial handling apparatus comprising a material handling vehicle,first track means for guiding movement of said vehicle along a mainaisle, a plurality of second track means each of which extends along anassociated one of a plurality of secondary aisles, said second trackmeans terminating short of intersection with said first track means,said first track means including a plurality of pairs of lengths oftrack, each pair of which is movable between a first position spanningan associated one of said secondary aisles to guide movement of saidvehicle along the main aisle past the associated secondary aisle and asecond position forming an extension between the associated one of saidsecond track means and said first track means to guide movement of saidvehicle from the main aisle into the associated secondary aisle, andmeans on said vehicle for effecting movement of said pairs of lengths oftrack from their first position to their second position.
 8. A materialhandling apparatus as set forth in claim 7 wherein said means on saidvehicle for effecting movement of said pairs of lengths of trackincludes means for pivoting one length of track of a pair of lengths oftrack in a clockwise direction about a first axis and means for pivotingthe other length of track of the pair of lengths of track in acounterclockwise direction about a second axis.
 9. A material handlingapparatus as set forth in claim 8 wherein said means for pivoting saidlengths of track includes a first arm pivotally mounted on the vehicleand engageable with the one length of track and a second arm pivotallymounted on the vehicle and engageable with the other length of track anddrive means on the vehicle for simultaneously pivoting said first andsecond arms in opposite directions relative to the vehicle to move apair of lengths of track from the first position to the second position.